991317 has 4 divisors (see below), whose sum is σ = 1321760. Its totient is φ = 660876.

The previous prime is 991313. The next prime is 991327. The reversal of 991317 is 713199.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 713199 = 3 ⋅237733.

It is not a de Polignac number, because 991317 - 2² = 991313 is a prime.

It is a D-number.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 165217 + ... + 165222.

It is an arithmetic number, because the mean of its divisors is an integer number (330440).

2⁹⁹¹³¹⁷ is an apocalyptic number.

It is an amenable number.

991317 is a deficient number, since it is larger than the sum of its proper divisors (330443).

991317 is a wasteful number, since it uses less digits than its factorization.

991317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330442.

The product of its digits is 1701, while the sum is 30.

The square root of 991317 is about 995.6490345498. The cubic root of 991317 is about 99.7097248855.

The spelling of 991317 in words is "nine hundred ninety-one thousand, three hundred seventeen".